West Control Solutions 8700+ - Manual (Page 161)

1 /
4
-DIN, 1 /
8
-DIN & 1 /
16
- DIN Controllers & Indicators - Product Manual
Page 156
Glossary 59305, Issue 7 – March 2014
Setpoint Select Type: Controller Parameter
This Operator Mode parameter is available if the remote setpoint feature is in use and
setpoint select is enabled, Setpoint Select defines whether the local or the remote setpoint
will be the Active Setpoint. It can be set to

,

, or

. If a digital input has been
configured for local/remote setpoint selection, the default setting is

. This means the
status of the digital input will determine which setpoint is active. Otherwise the user can only
choose

, or

.
The active setpoint is indicated by prefixing its legend with the “ “
character. E.g. the local setpoint legend is

, when it is active and

when it is inactive.
If a digital input has been configured to select local/remote SP, setting Setpoint Select to

, or

will override the digital input and the active SP indication changes to .
Display code =

.
Also refer to Active Setpoint, Remote Setpoint, Setpoint and Setpoint Select Enable.
Setpoint Select Enable Type: Controller Parameter
If the remote setpoint feature is in use, this determines whether operator selection of
setpoints is enabled or disabled. If enabled, the Setpoint Select parameter is available in
operator mode. If Setpoint Select is disabled again, the active setpoint will remain at its
current status.
Display code =

, default setting =

(disabled).
Also refer to Remote Setpoint and Setpoint.
Solid State Relay (SSR) Type: General Definition
An external device manufactured using two Silicone Controlled Rectifiers, which can be used
to replace mechanical relays in most AC power applications. As a solid state device, an SSR
does not suffer from contact degradation when switching electrical current. Much faster
switching cycle times are also possible, leading to superi
or control. The instrument’s SSR
Driver output is a time proportioned 10VDC pulse, which causes conduction of current to the
load when the pulse is on.
Also refer to Cycle Time, Time Proportioning Control, and Triac.
Solenoid Valve Type: General Definition
An electromechanical device to control gas or liquid flow. It has just two states, open or
closed. A spring holds the valve closed until a current is passed through the solenoid coil
forces it open. Standard Process Controllers with Time Proportioned outputs are used to
control solenoid valves.
Solenoid valves are often used with high/low flame gas burners. A bypass supplies some gas
at all times, but not enough to heat the process more than a nominal amount (low flame). A
controller output opens the solenoid valve when the process requires additional heat (high
flame)..
Also refer to Modulating Valves and Time Proportioning Control.